Had a crack at a sub 500 build with that case:
PCPartPicker part list:
http://pcpartpicker.com/p/XrMqhM
CPU: Intel Pentium G3220 3.0GHz Dual-Core Processor ($58.99 @ Amazon)
Motherboard: Gigabyte GA-B85M-D2V Micro ATX LGA1150 Motherboard ($49.33 @ Newegg)
Memory: A-Data XPG V2 8GB (2 x 4GB) DDR3-1600 Memory ($85.98 @ Newegg)
Storage: A-Data Premier Pro SP600 128GB 2.5" Solid State Drive ($64.99 @ TigerDirect)
Video Card: PowerColor Radeon R7 260X 1GB Video Card ($69.99 @ Newegg)
Case: Corsair 200R ATX Mid Tower Case ($39.99 @ NCIX US)
Power Supply: Corsair Builder 430W 80+ Bronze Certified ATX Power Supply ($19.99 @ Newegg)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($89.99 @ NCIX US)
Total: $479.25
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-06-02 08:13 EDT-0400)
If you can get that powercolor GPU at that reduced rate from newegg you would be laughing. Can't quite make the same build with AMD, but you could go with an Athlon x4 760k and an FM2 / FM2+ board.